Gaseous electric discharge lamp device



March-12, 1935. DQRGELQ 1,994,305

GASEOUS ELECTRIC DISCHARGE LAMP DEVICE Filed Sept. 18, 1934 I INVENTOEQ- .QZIQ-QW BY 4! AT ORNEY v Patented Mar. 12, 1935 ni h stares arem GFFWE GASEOUS ELECTRIU DISGHARGE LAMP DEVICE Eduard G. lilorgelo, Eindhoven, Netherlands, assignor to General Electric Company, a corporation of New York Application September 18, 1934, Serial No. 744,486 In Germany September 30, 1933 2 @laims. (Cl. lid-124) -The present invention relates to gaseous electerminal of the current source. After breaking tric discharge lamp devices generally and more the connection between the current lead and the particularly the invention relates to illuminating point of higher potential, the choke coil or the systems incorporating such devices. resistance which has made the switching possible 5 The starting potential of gaseous electric diswithout danger of interrupting the discharge in 5 charge lamps is appreciably higher than the opthe lamps is short circuited. erating voltage thereof and these lamps are op- The potential supplied by the current supply erated in series with an impedance which absource thus need be only sufficient to operate the sorbs the difierence between the starting and lamps and need not be sufficient to start the the operating voltage when said lampsare oplamps. The size of the external series imped- 10 crating. When this external impedance consists ances for the lamps thus can be considerably of an ohmic resistance an appreciable amount smaller than in the case where the voltage of the 'of energy is wasted and when choke coils are current source is suflicient to start the lamps for used for thispurpose the performance factor in the present case the impedances do not absorb it is the difference between the starting and the op- The object of the present invention is to procrating voltages of the lamps in the circuit durvide an illuminating system comprising a plu- ,ing the operation of the lamps. rality of gaseous electric discharge lamp devices If the discharge lamps contain a metal dimcult which is more emcient than prior systems into vaporize, for instance, sodium, the vapor of 2c corporating such devices. Another object of the which must have a certain pressure for particiinvention is to provide an illuminating system pation in the light emission, then it is advisable the manufacturing cost of which is reduced to a to maintain for some time the connection with minimum. Still further objects and advantages the point of higher potential after the start of attaching to the device and to its use and operathe discharge lamps. The lamps are then temtion will be apparent to those skilled: in the art porarily overloaded and rapidly heated to their 5 from the following particular description. operating temperature.

In accordance w'th these objects the illumi- When, during starting of the lamps, the curnating system comprises a plurality of discharge rent lead thereof is connected to the point of lamps connected across the terminals of a curhigher potential, then the above mentioned self- .30 rent source the voltage of which is not capable induction or the resistance is connected between of starting the lamps. One of the current leads this point and the terminal of the current source for the lamps is connected to one terminal of with which this current lead is directly connectthe current source through a resistance, or prefed after the starting of the lamps. The choke erably through a'choke coil, and a switch is procoil or resistance prevents a short circuit between a vided by which this current lead is temporarily the higher potential point and the terminal. The 5 connected with a point which, in regard to the choke coil or the resistance is short circuited after other terminal of the current source, has a pothe connection between this point of higher potentential of sufficient magnitude to start the lamps. tial and the current lead has been broken. Dur- ,The system also comprises means for short-ciring the time between this interruption and the to cuiting the above mentioned resistance or the short circuit of the choke'coilpr of the resist- 40 choke coil. ance the latter are connected in series with the When the system is started into operation the discharge lamps. The self-inductance or the choke coil or the resistance is connected into the resistance must therefore be so dimensioned that circuit and the switch connects the current lead the discharge in the lamps is not interrupted with the point of higher potential. After the during this period. On the other hand they 45 discharge lamps have been'started by this higher must be so dimensioned that a short circuit or potential the connection between the lamps and too great a current between the point of higher the higher voltage point is broken. Potential is potential and the above mentioned terminal of always impressed on the discharge lamps even the current source is avoided. In many cases a when this connection is broken since the current resistance does not meet both requirements and 50 lead is connected to the terminal of the current therefore the use of a choke coil is preferred. source over the choke coil or the resistance. The connection to the point of higher potential The discharge in the lamps is thus maintained in and the bridging of the choke coil or of the the lamps when the current lead is disconnected resistance are preferably made with the same from the high potential and connected to the switch. 5 5

In the drawing accompanying and forming part of this specification three circuits embodying the invention are shown schematically.

Like numbers denote like parts in the figures.

Referring to Fig. 1 of the drawing the new and novel circuit comprises a number of gaseous electric discharge lamps 1 connected in parallel. Each of said lamps 1 is connected in series with a choke coil 2 between the current leads 3 and 4. Each of the discharge lamps 1 comprises thermionic electrodes and a gaseous atmosphere comprising a starting gas and the vapor of a difiicultly vaporizable material, such as sodium. The current lead 3 is. connected to the terminal 5 of the secondary transformer coil 6, while the lead 4 is connected to the terminal 9 of said secondary 6 through the choke coil '7 which is short-circuited, when desired, by the switch 8. Said lead 4 is connected by switch 10 to the end 11 of a special transformer coil 12 the other end of which is connected to the terminal 9.

When potential is applied to the above described circuit the switch 8 is open and the switch 10 is closed so that the potential between the point 11 and the terminal 5 of the transformer is conducted to the discharge lamps 1 which starts said lamps 1. Then the switch 10 is opened. After the opening of switch 10 the lamps 1 are connected across the terminals 9 and 5 of the transformer through the choke coil '7 so that the discharge in said lamps 1 is maintained. The choke coil '7, which is required in order to avoid a short circuit between the point 11 and the terminal 9 when switch 10 is in its closed position, is then short circuited by means of the switch 8 so that the current lead 4 is connected directly to the terminal 9.

The circuit shown in Fig. 2 comprises a three phase star connected transformer having terminals 13 and 1'! and the mid-point 14. The current lead 3 of the discharge lamps 1 is connected to the terminal 13; the lead 4, through the choke coil 7, is connected to the zero point 14, while the latter lead 4 can also be connected by the switch 15 and the contact 16 to the terminal 17. The switch 15 can also be brought into contact with contact 18 which short circuits the choke coil 7.

The above described circuit is started into operation bymoving the switch 15 into contact with contact 16 so that the voltage across the terminals 13 and 17 is applied to the lamps 1, which starts the lamps 1. After the lamps 1 have been started the switch 15 is moved from contact 16 to contact 18 whereby the connection between the current lead 4 and the terminal 17 is broken, the choke coil 7 is short circuited and the lead 4 is connected directly to the zero point 14 in sequence and the potential applied to the lamp circuit during operation of the directly or, when desired, through small transformers, the primary circuits of which are connected in series.

The end 27 of the series circuit is connected to the terminal 25 through the choke coil 7 and is connected to the high potential point 22by switch 15, when desired.

As shown in Fig. 3 a plurality of gaseous electric discharge lamps are connected in series across the terminals 24 and 28 and the terminals 25 and 28 as well as the terminals 24 and 25, when desired.

The lamps in each of these series circuits are started in the manner described in connection with Fig. 2.

Since the special transformer coils used to produce the higher potentials are in use but a short time they are wound of thin wires without danger, when disered, which reduces the manufacturing cost of the illuminating system.

While I have described my invention in connection with sodium vapor lamps it will be understood of course that I contemplate the use of lamps having the vapor of other metals as a .light giving element, such as cadmium, magnesium, thallium, mercury, zinc or caesium, or amalgams or mixtures thereof, in my new and novel illuminating system.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. An illuminating system comprising in combination a plurality of gaseous electricdischarge lamp devices, a transformer therefor, the starting voltage of said lamp devices being higher than the voltage across two terminals of said transformer and the operating voltage of said lamp devices being equal to the voltage across said transformer terminals, said transformer having a point thereon which supplies a higher voltage with respect to one of said terminals than that supplied by said terminals, said devices being connected through an impedance across two terminals of said transformer, means to connect said devices across said point and one of said terminals during the starting of said lamps and to connect said devices across the terminals of said transformer during the operation of said lamps and means to short circuit said impedance during the operation of said devices.

2. An illuminating system comprising in combination a plurality of gaseous electricdis-,

charge metal vapor lamp devices, a transformer therefor, the starting voltage of said lamp devices being higher than the voltage across two terminals of said transformer and the operating voltage of said'lamp devices being equal to the voltage across said transformer terminals, said transformer. having a point thereon which supplies a highervoltage with respect to one of said terminalslthan that supplied by said terminals, said devices being connected through an impedance across two terminals .of said transformer, means to connect said devices across said point and one of said terminals during the starting of said lamps and to connect said devices across the terminals of said transformer during the operation of said lamps and means to short circuit said impedance during the operation of said devices.

EDUARD G. DORGELO. 

